This invention relates to methods and apparatuses for fastening circuit boards to computer chassis, for example by biasing the circuit boards against mounting members of the chassis.
Computers typically include a chassis that houses semiconductor devices, such as memory chips, processors, and linking circuitry mounted to a printed circuit board. The printed circuit board is typically attached with threaded fasteners to standoffs, which are then attached to a surface of the chassis. Accordingly, the stand-offs secure the circuit board to the chassis while leaving a gap between the surface of the circuit board and the surface of the chassis. The gap is typically sized to prevent the devices and connecting circuitry mounted on the circuit board from contacting the chassis, which could cause the devices to short circuit.
One problem with the above design is that it can be time consuming to first threadably attach the stand-offs to each circuit board and then threadably attach each stand-off to the chassis. One approach to address this problem is to attach the circuit board to a plurality of rails with threaded fasteners and then slideably attach the rails to the chassis. One such arrangement is an NLX circuit board available from Intel Corp. of Santa Clara, Calif. The foregoing approach, however, can also have certain drawbacks. For example, it may be difficult and/or intimidating for end users of the computer to remove the circuit board for service or replacement because tools may be required to fasten and unfasten the connection between the circuit board and the rails. Alternatively, if the rails remain attached to the circuit board during servicing, then the rails are not available to fasten a substitute circuit board to the chassis, and the computer may be inoperable during this period.
Another conventional arrangement includes unthreaded stand-offs connected between the chassis and the circuit board and a bracket that engages the circuit board and fastens to a wall of the chassis with an external screw. Such an apparatus is available from Palo Alto Design Group of Palo Alto, Calif. One drawback with this arrangement is that users can deliberately or accidentally loosen the external screw without realizing that they may also loosen the circuit board within the chassis. Another disadvantage is that the external screw must generally be loosened with a tool, which can be intimidating to the end user. Still another disadvantage is that, in addition to loosening the external screw, each unthreaded stand-off must be individually disengaged from the circuit board before the circuit board can be removed from the chassis.
The present invention is directed toward methods and apparatuses for removably securing circuit boards to computer chassis. The apparatus can include a moveable mounting member with an engaging surface positioned to engage a portion of the circuit board. In one embodiment, the moveable mounting member is attached to a mounting bracket that is movable relative to the chassis. A biasing device is coupled between the mounting bracket and the computer chassis and is adjustable between a first position and a second position. When the biasing device is in the second position, the moveable mounting member is biased against the portion of the circuit board.
In one particular aspect of the invention, the biasing device is operable only from within the chassis. In another aspect of the invention, the moveable mounting member can be the second of at least two mounting members, and can engage a second portion of the circuit board. The apparatus can further include a first mounting member projecting away from a surface of the chassis and having a first engaging surface positioned to engage a first portion of the circuit board. In yet another aspect of the invention, the moveable mounting member is securely engaged with the circuit board when the biasing device is in the second position and is loosely engaged with or disengaged from the circuit board when the biasing device is in the first position. In still another aspect of the invention, the biasing device can include a threaded shaft that engages a threaded shaft aperture of the mounting bracket and has a knob for manually rotating the shaft relative to the shaft aperture to move the shaft between the first position and the second position.
The present invention is also directed toward a method for removably coupling a circuit board to a computer chassis. The method can include engaging a portion of the circuit board with a moveable mounting member connected to a bracket. The moveable mounting member is biased into engagement with the circuit board by operating a biasing device from within the chassis. The method can further include placing a region of the circuit board in tension or compression. In one aspect of the invention, the moveable mounting member is the second of at least two mounting members and engages a second portion of the circuit board. The method can further include engaging a first portion of the circuit board with a first mounting member connected to the computer chassis.
In a method in accordance with another aspect of the invention, at least one mounting member is connected to the chassis and the circuit board is biased toward or away from a surface of the chassis. In still another aspect of the invention, the mounting member can be the first of at least two mounting members connected to the chassis with a first portion of the circuit board biased against the first mounting member and a second portion of the circuit board biased against the second mounting member, placing at least one of the first and second portions of the circuit board in tension or compression in a plane of the circuit board.